Inorganic iodine in the tropical upper troposphere and lower stratosphere as derived from balloon-borne solar occultation observations

The budget and photochemistry of iodine is assessed in the tropical Upper Troposphere/ Lower Stratosphere (UT/LS) where the halogen source gases enter the stratosphere and supply the stratosphere with halogen species. Two stratospheric balloon flights of the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectrometer) payload were performed from a tropical station in north-eastern Brazil (5°S, 43°W) in June 2005 and June 2008. The LPMA/DOAS payload conducted spectroscopic direct sun measurements in the UV/visible and infrared spectral range during balloon ascent/descent and in solar occultation geometry. Here we focus on the outcome of the occultation measurements during sunrise and sunset.